Rashi D"H V'im yim'at habbayyit...(Bo 12:4 )
First, Rashi says, "X l'fee f'shuto..." Namely, if there aren't enough people to completely eat the Pesach lamb, and they will come to have Nottar, then these people are to join their neighbors.
V'od yeish bo Midrash: "That following 'shenimnu' they may still withdraw whilst the lamb still lives". Rashi does NOT force the P'shat to conform to D'rash EVEN when that D'rash is Halachic and not Aggadic.
Thus, P'shat of a phrase can be independent of the Halachot derived from it . Even though the p'shat here IS influenced by Halachah. It conforms to an explicit text concerning Nottar. Although we can't be certain, it doesn't seem to CONTRADICT halachah either!
While Rashi does suggest that P'shat conforms with Halachah, he also mentions that Halachic D'rash adds a dimension that goes well beyond P'shat.